Organic gallium compounds in epoxy resin as standards for the determination of gallium in biological tissues with an electron probe microanalyzer

1980 ◽  
Vol 52 (3) ◽  
pp. 532-536 ◽  
Author(s):  
Kayoko. Nakamura ◽  
Hirotake. Orii
Keyword(s):  
Epoxy Resin ◽  
Electron Probe ◽  
Biological Tissues ◽  
Electron Probe Microanalyzer ◽  
Gallium Compounds

Correction for Non-Linearity of Proportional Counter Systems in Electron Probe X-Ray Microanalysis

1965 ◽  
Vol 9 ◽  
pp. 208-220 ◽  
Author(s):  
Kurt F. J. Heinrich ◽  
Donald Vieth ◽  
Harvey Yakowitz
Keyword(s):  
Theoretical Basis ◽  
Electron Probe ◽  
Dead Time ◽  
Pulse Height ◽  
The Other ◽  
Time Effects ◽  
X Ray ◽  
Electron Probe Microanalyzer ◽  
Intensity Measurements

AbstractWhile the theoretical basis for the correction of non-linearity of detector systems is well known, methods for the determination of dead-time effects must be adapted to electron probe microanalyzer systems. Two such methods, one employing both X-ray and current measurements and the other employing simultaneous X-ray measurements on two spectrometers, are described. The effect of pulse-height shrinkage at high counting rates on the linearity of the detector system is discussed. When the proposed corrections for the dead-time of X-ray detector systems employing proportional counters are applied to the X-ray intensity measurements obtained with the electron probe microanalyzer, count rates as high as 50,000 counts/sec can be used.

Composition of Garnet in Anorthosite–Charnockite Suites: Bias and Precision in Electron-Probe Microanalysis

1973 ◽  
Vol 10 (8) ◽  
pp. 1257-1266 ◽  
Author(s):  
K. Schrijver
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Physical State ◽  
Total Iron ◽  
Electron Probe Microanalyzer ◽  
Unknown Species ◽  
Compositional Homogeneity

The composition of garnet in each of 11 specimens from anorthosite–charnockite suites (Marcy Massif, Morin Complex, Lac-Croche Complex) has been determined by electron-probe microanalyzer. All analyses include Si, Al, Fe, Mn, Mg, and Ca. The range of FeO (total iron as Fe2+) is from 26.5 to 34 wt.%; MnO from 0.5 to 2, MgO from 0.5 to 5, and CaO from 7 to 9.5 wt.%. TiO2 is present in very small amounts at most ([Formula: see text]?). The major end member molecule in all specimens is almandine.Bias and precision of the analysis have been estimated: (1) by replicate determination of the composition of a garnet standard in each analytical run on each of the unknown species and (2) by duplicate determination of the garnet species in each rock specimen.In general, inclusion of a known species, similar in composition and physical state to the unknown species, in each analytical run on an unknown will provide estimates of bias applicable to individual analyses as well as an overall estimate of bias applicable to the mode and circumstances of the particular series of runs on the electron-probe microanalyzer. The reliability of the estimates of bias so obtained depends mainly on the compositional homogeneity of both known and unknown species.

Metallurgical Applications of Electron Probe Microanalysis

1959 ◽  
Vol 3 ◽  
pp. 197-212 ◽  
Author(s):  
David B. Wittry
Keyword(s):  
Electron Probe ◽  
Diffusion Profile ◽  
Physical Metallurgy ◽  
California Institute ◽  
Electron Probe Microanalyzer ◽  
California Institute Of Technology ◽  
Intermediate Phases ◽  
Institute Of Technology ◽  
Single Crystal Sapphire

AbstractThe electron probe microanalyzer has found numerous applications in physical metallurgy. Some recent problems which have been studied with the microanalyzer constructed by the author at the California Institute of Technology include (1) determination of the penetration of chromium in chromized iron, (2) determinations of the concentration of nickel in taenite bands occurring in a fragment of meteorite from Canyon Diablo, (3) identification of intermediate phases in the as-cast structure of an alloy of titanium and copper, (4) identification of phases in the titanium—silver binary system, (5) determination of concentration fluctuations in a gold—copper alloy resulting from slow solidification, and (6) determination of the diffusion profile of nickel in single crystal sapphire.

Reduction of Potassium in Kidney Proximal Tubules to Aid in Electron Probe X-Ray Microanalysis of Calcium

1985 ◽  
Vol 43 ◽  
pp. 474-475
Author(s):  
A. LeFurgey ◽  
P. Ingram ◽  
L.J. Mandel
Keyword(s):  
Smooth Muscle ◽  
Proximal Tubule ◽  
Electron Probe ◽  
Clinical Applications ◽  
Proximal Tubules ◽  
Rabbit Kidney ◽  
Target Cells ◽  
X Ray ◽  
Freeze Dried

For quantitative determination of subcellular Ca distribution by electron probe x-ray microanalysis, decreasing (and/or eliminating) the K content of the cell maximizes the ability to accurately separate the overlapping K Kß and Ca Kα peaks in the x-ray spectra. For example, rubidium has been effectively substituted for potassium in smooth muscle cells, thus giving an improvement in calcium measurements. Ouabain, a cardiac glycoside widely used in experimental and clinical applications, inhibits Na-K ATPase at the cell membrane and thus alters the cytoplasmic ion (Na,K) content of target cells. In epithelial cells primarily involved in active transport, such as the proximal tubule of the rabbit kidney, ouabain rapidly (t1/2= 2 mins) causes a decrease2 in intracellular K, but does not change intracellular total or free Ca for up to 30 mins. In the present study we have taken advantage of this effect of ouabain to determine the mitochondrial and cytoplasmic Ca content in freeze-dried cryosections of kidney proximal tubule by electron probe x-ray microanalysis.

Quantitative EPMA of nitrogen : A tricky element in the electron-probe microanalyzer

1992 ◽  
Vol 50 (2) ◽  
pp. 1622-1623
Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers
Keyword(s):  
Background Subtraction ◽  
Electron Probe ◽  
Detection System ◽  
Higher Order ◽  
Light Elements ◽  
Strong Suppression ◽  
Electron Probe Microanalyzer ◽  
Quantitative Epma ◽  
Peak Count ◽  
Lead Stearate

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.

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